Khan.scratchpad.disable(); Tiffany sells magazine subscriptions and earns $$3$ for every new subscriber she signs up. Tiffany also earns a $$22$ weekly bonus regardless of how many magazine subscriptions she sells. If Tiffany wants to earn at least $$80$ this week, what is the minimum number of subscriptions she needs to sell?
Explanation: To solve this, let's set up an expression to show how much money Tiffany will make. Amount earned this week $=$ $ $ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus Since Tiffany wants to make at least $$80$ this week, we can turn this into an inequality. Amount earned this week $\geq $80$ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus $\geq $80$ We are solving for the number of subscriptions sold, so let subscriptions sold be represented by the variable $x$ We can now plug in: $x \cdot $3 + $22 \geq $80$ $ x \cdot $3 \geq $80 - $22 $ $ x \cdot $3 \geq $58 $ $x \geq \dfrac{58}{3} \approx 19.33$ Since Tiffany cannot sell parts of subscriptions, we round $19.33$ up to $20$ Tiffany must sell at least 20 subscriptions this week.